Gas generator provided with a safety device for slow warm-ups

Abstract

The present invention relates to a gas generator ( 10 ) comprising a body ( 12 ) delimiting at least one part of a combustion chamber ( 20 ), said part housing a primary pyrotechnic charge ( 16 ) adapted to generate gases in the combustion chamber ( 20 ) when said charge is initiated in combustion, and a slide valve ( 60 ) located outside said body ( 12 ) and defining with the latter a second chamber ( 66 ) housing a secondary pyrotechnic charge ( 74 ) whereof the self-ignition temperature is less than that of the primary pyrotechnic charge ( 16 ). A gas flow channel ( 50 ) for flowing gas out of the combustion chamber ( 20 ) is formed in the body ( 12 ). According to the invention, the slide valve ( 60 ) blocks this channel when it is in a first position, and under the effect of gases released by said secondary pyrotechnic charge ( 74 ), the slide valve is adapted to move to a second position wherein the channel ( 50 ) is no longer sealed off, allowing the gases contained in the combustion chamber ( 20 ) to flow outwards to the exterior.

The invention claimed is: 
     
       1. A gas generator comprising:
 a body delimiting at least a part of a combustion chamber, said part housing a primary pyrotechnic charge adapted to generate gases in the combustion chamber when said charge is initiated in combustion, and 
 a slide valve located outside said body and defining with the latter a second chamber housing a secondary pyrotechnic charge whereof the self-ignition temperature is less than that of the primary pyrotechnic charge, 
 wherein a gas flow channel for flowing gas out of the combustion chamber is formed in the body, 
 wherein the slide valve blocks the gas flow channel when it is in a first position, and 
 wherein, under the effect of gases released by said secondary pyrotechnic charge, the slide valve is adapted to move to a second position wherein said channel is no longer blocked, allowing gases contained in the combustion chamber to flow outwards to the exterior. 
 
     
     
       2. The gas generator according to  claim 1 , wherein the slide valve is capable of moving by sliding as per a rectilinear trajectory. 
     
     
       3. The gas generator according to  claim 1 , wherein the gas flow channel comprises a plurality of holes distributed over the circumference of the body. 
     
     
       4. The gas generator according to  claim 1 , wherein the slide valve comprises at least one opening adapted to communicate with the flow channel for the gas when the slide valve is in its second position, the gas contained in the combustion chamber then able to flow towards the exterior through said flow channel and said opening. 
     
     
       5. The gas generator according to  claim 4 , wherein the opening comprises a circumferential groove formed on the internal face of the slide valve and at least one hole terminating in said groove and on the external face of said slide valve, said groove delimiting an annular chamber with the body when the slide valve is in its first position and being adapted to communicate with the gas flow channel when the slide valve is in its second position. 
     
     
       6. The gas generator according to  claim 4 , wherein the gas flow channel comprises a circumferential groove formed on the external face of the body and at least one hole terminating in said groove and on the internal face of said body, said groove delimiting an annular chamber with the slide valve when the latter is in its first position and being adapted to communicate with its opening when the slide valve is in its second position. 
     
     
       7. The gas generator according to  claim 1 , wherein the slide valve is coaxial to the body. 
     
     
       8. The gas generator according to  claim 1 , wherein the body comprises at least one first section having a first diameter and a second section of greater diameter located in the extension of the first section, a shoulder being defined between the first and the second section, and wherein the slide valve comprises a first part adapted to slide along the second section and a second part extending radially towards the interior and whereof the internal radial face is adapted to slide along the first section, the second chamber ( 68 ) being defined between the shoulder and the second part of the slide valve. 
     
     
       9. A device to be actuated comprising a gas generator according to  claim 1 , wherein the gases emitted by the primary pyrotechnic charge of the gas generator when it is initiated in combustion are adapted to actuate said device. 
     
     
       10. The device to be actuated according to  claim 9 , comprising a payload ejection device. 
     
     
       11. The device to be actuated according to  claim 9 , comprising a cylinder.